package com.liu.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

//操作数据库的公共类
public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;

    //静态代码块，类加载的时候初始化
    static{
        //通过类加载器读取对应资源
        InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        Properties properties = new Properties();

        try{
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }

        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        username = properties.getProperty("username");
        password = properties.getProperty("password");
    }

    //获取数据库的连接
    public static Connection getConnection(){
        Connection connection = null;
        try {
            Class.forName(driver);
            //connection = DriverManager.getConnection(url, username, password); // ✅ 正确：赋值给connection
            // AI提示错误：没有赋值给connection
            connection = DriverManager.getConnection(url, username, password);//修改：2025-8-8 14：07 将其赋值给connection
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return connection;
    }

    //编写查询公共类
    public static ResultSet execute(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet,String sql,Object[] params) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++){
            preparedStatement.setObject(i+1, params[i]);
        }

        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }

    //编写增删改的公共方法
    public static int execute(Connection connection,PreparedStatement preparedStatement,String sql,Object[] params) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++){
            preparedStatement.setObject(i+1, params[i]);
        }

        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }

    //释放资源
    public static boolean closeResource(Connection connection,PreparedStatement preparedStatement,ResultSet resultSet){
        boolean flag = true;

        if (resultSet != null){
            try {
                resultSet.close();
                resultSet = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }

        if (preparedStatement != null){
            try {
                preparedStatement.close();
                preparedStatement = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }

        if (connection != null){
            try {
                connection.close();
                connection = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }

        return flag;
    }

}
